Comparative Pharmacology
Head-to-head clinical analysis: CONSTILAC versus POLYETHYLENE GLYCOL 3350.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CONSTILAC versus POLYETHYLENE GLYCOL 3350.
CONSTILAC vs POLYETHYLENE GLYCOL 3350
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Constilac (lactulose) is a synthetic disaccharide that is not absorbed in the small intestine. In the colon, it is metabolized by bacteria to short-chain fatty acids (e.g., lactic acid), which osmotically draw water into the bowel, producing a laxative effect. Additionally, in hepatic encephalopathy, the acidification of colonic contents traps ammonia (NH3) as ammonium (NH4+), reducing its absorption.
Osmotic laxative. Polyethylene glycol 3350 is a non-absorbable polymer that retains water in the colon via hydrogen bonding, increasing stool water content and stimulating defecation.
Oral, 15-45 mL (10-20 g lactulose) once daily, titrated to produce 2-3 soft stools daily; may be given as a single dose or divided twice daily. Onset of action 24-48 hours.
17 g (1 capful or packet) dissolved in 4–8 oz (120–240 mL) water, administered orally once daily for constipation; for colonoscopy preparation, 240 g (4 L of solution) ingested at 240 mL every 10–15 minutes.
None Documented
None Documented
Not applicable due to negligible systemic absorption; lactulose acts locally in the colon.
Terminal elimination half-life is 1-2 hours in patients with normal renal function; prolonged in renal impairment, but clinical impact minimal due to primarily fecal elimination.
Primarily fecal as unchanged drug (systemic absorption negligible). Renal excretion accounts for <2% of any absorbed fraction. Biliary excretion is minimal.
Renal: approximately 20% excreted unchanged; Fecal: approximately 80% eliminated unchanged in feces.
Category C
Category C
Osmotic Laxative
Osmotic Laxative